I’d stopped by the SS office when I started getting all kinds of stuff in the mail. They said the same - it could be done online or I could make an appointment to do it there. I opted to make the appointment. I just prefer in-person since I have questions about Medicare. With luck, I won’t have to wait long with the appointment. If we lived in a large city, it might be different but this is Podunk Nowhere. :-)
Small town offices can be a good thing.
My boss got a surprise with his first Medicare premium - he told me they set the premium based on the prior year’s income. He got them to adjust it downward after explaining that he had taken a large sum of money from his IRA to pay off his house, and that his income from salary was far less than they thought.